Pyrimethanil is a synthetic compound of the chemical group Anilinopyrimidine. Pyrimethanil is known to act as a pesticide, particularly a fungicide, to provide preventative and curative control of diseases of plants, seeds, and crops.
One mechanism of action by which pyrimethanil has been shown to act as a fungicide is to inhibit methionine biosynthesis, and thus affects protein formation and subsequent cell division. Pyrimethanil has also been shown to block the ability of fungi to degrade and digest plants, thereby inhibiting penetration and development of pathogenic disease and infection. Pyrimethanil has also been described as having a thermal decomposition temperature ranging from 189.54° C. to about 344.74° C. (Agriphar Pyrimethanil (ISO) Safety Data Sheet, revised Sep. 7, 2012, version 8.1).
Traditionally, postharvest fungicides are applied to plants, seeds, and crops as a water-based solvent emulsions for use in spray or drench applications during sorting and packing operations. Some crops, such as soft fruits, including berries or table grapes, are very susceptible to fungal pathogens, but are not tolerant of the free moisture present in traditional fungicide applications. Therefore, treatment of soft fruits with traditional fungicides is problematic. Other crops, such as apples and oranges, can tolerate the moisture of traditional fungicides, but the drenching operation typically used to apply a fungicide is costly, time consuming, requires excessive volumes of pesticide treated water, and spreads spores of non-susceptible pathogens that contribute to fungicide-resistant pathogen populations.
Some postharvest fungicide treatments are delivered via fogging, which is typically administered in a cold temperature (below room temperature). However, this technique has problems with uniform distribution onto the crops. For example, deposition rates of a fungicide may be too high, and exceed regulatory maximum residue limits.
Alternatively, deposition rates of a fungicide may be too low and fall below the minimum required for efficacy. In addition, fungicide fogging operations are not successfully performed when cooling circulation fans are operating in the room or chamber. These fans are essential to the important fruit cooling preservation process, so having them off during the fungicide fogging operation is a negative feature of this sort of application as it contributes to undesirable warming of the stored crop. In a storage room, fungicide application efficacy is closely tied to uniformity of distribution. Ultimately, more uniformity and even distribution on the crop of pesticide or fungicide treatments improves the efficacy of such treatments to inhibit and/or control plant pathogens.
The present disclosure describes methods of administering traditional pesticides in non-traditional ways for use in antimicrobial protection of crops to inhibit plant pathogens. More specifically, the present disclosure provides methods of using vaporized pyrimethanil as an antimicrobial protection to post-harvest plants, plant parts, and seeds that are advantageous to other previously described antimicrobial treatments of plants. Ultimately, the methods described herein provide beneficial delivery options for established pesticides and application systems.